console.log(
    [1, , 3][1],
    [1, 2, 3, a] + 1,
    [1, 2, 3, 4] + 1,
    [1, 2, 3, a][0] + 1,
    [1, 2, 3, 4][0] + 1,
    [1, 2, 3, 4][6 - 5] + 1,
    [1, , 3, 4][6 - 5] + 1,
    [
        [1, 2],
        [3, 4],
    ][0] + 1,
    [
        [1, 2],
        [3, 4],
    ][6 - 5][1] + 1,
    [[1, 2], , [3, 4]][6 - 5][1] + 1
);
